Packet filtering firewall is one of the most important mechanisms used by corporations to enforce their security policy. Recent years have seen a lot of research in the area of firewall management.

A group of hackers that security researchers call LightBasin has been compromising mobile telecommunication systems across the world for the past five years. Since 2019, the group hacked into more ...

# iptables -A INPUT -p tcp -m tcp -m multiport ! --dports 80,443 -j DROP # iptables -A INPUT -p tcp -m tcp -m multiport --dports 80,443 -j ACCEPT # iptables -A INPUT -m conntrack -j ACCEPT --ctstate ...

The Ohio State University has numerous memorable traditions surrounding its football program, yet few compare to "Script Ohio." The tradition that started in The unlikely history behind "Script Ohio:" ...

After securing systems by hiding them completely from the network/internet using Single Packet Authorization, I’ve recently been interested in doing more so-called ‘active’ defense, by implementing ...

Iptables, more properly referred to as “iptables/netfilter” because of the two modules that are involved — the userspace module “iptables” and the kernel ...

Dear readers, I appear to have set a Paranoid Penguin record—six months spent on one article series. (It has consisted of five installments, with a one-month break between the second and third pieces.

I've been writing a multipart series on building a transparent (bridging) firewall using Linux. Specifically, I'm using the distribution OpenWrt running on a Linksys WRT54GL broadband router, a ...

Giobbi, R., 2009: Bypassing Firewalls with IPv6 Tunnels. Carnegie Mellon University, Software Engineering Institute's Insights (blog), Accessed November 25, 2025 ...